Descartes: A Biography

end CUNYB/Clarke     December, :

Notes to Pages– 

curves which will be better than mine, it is no less ridiculous than the captains

of Italian comedies’ (i.). He asked Mersenne to keep this letter ‘between

ourselves’, but the letter found its way back to Beaugrand. By contrast, Descartes

wrote two letters to Mersenne to be forwarded to Fermat, onOctoberand

January,butbyJanuary he was complaining that he had received no reply

and that he had no intention of reading any more material by Fermat until he

received replies to earlier letters. It appears that Descartes’ letter of January,

forFermat, was forwarded to him only in May of that year.

.This was theMethodus ad disquirendum maximam et minimam et de tangentibus

linearum curvarum(Oeuvres,i.–.).

.By this stage Descartes knew the identity of the author, but thought it a sign of

civility to pretend otherwise, ‘so that he will realize that I respond only to his

writing’ (i.).

.Descartes against Roberval and Pascal,March,inwhich he refers to the

‘defenders’ of Fermat (ii.), and to the fact that Fermat ‘has friends who are taking

great pains to defend him’ (ii.). Descartes goes on to say that, since they have

taken the side of Fermat, in support of a position ‘as unsustainable from his side as

could be imagined’, he hopes they would not be his judges (ii.). The reference to

‘friends’ of Fermat is repeated in Descartes to Mydorge (March: ii.) and

in Descartes to Mersenne (March: ii.). Descartes says that he knows only

two people in Paris who would be competent in this context, Mr. Mydorge and

Mr. Hardy. He follows through on this estimate by writing to Mydorge, the same

day, listing all the correspondence between Fermat and himself, and asking that

he and Hardy adjudicate the controversy (Descartes to Mydorge,March:

ii.). Descartes later acknowledged to Mersenne that Roberval and Pascal did

not have ‘the special relation with Mr. Fermat that your letter made me imagine’

(Descartes to Mersenne,March: ii.). This gave him reason to hope that

they would quickly see the truth. Roberval also set the record straight, in a letter

to Mersenne in April,byexplaining that he and Pascal ‘know Mr. Fermat

and Mr. Descartes only by reputation’ (ii.).

.‘Combat’ is used in Descartes to Roberval and Pascal (March: ii.), and

the language of ‘seconds’ in a duel is used in Descartes to Huygens (March:

ii.).

.Descartes to Mersenne,March(ii.–). See also Descartes to Mersenne,

October:‘Ibeseech you to retain in your own hands all the papers that I

sent you which contain geometrical solutions, without giving them anything other

than copies if they request them. And if you have loaned them some which they

refuse to return, I ask you to request them for me’ (ii.–).

.This low opinion was repeated after his death. Descartes expressed regret when

he heard that Beaugrand had died in December(iii.). However, when

Mersenne forwarded one of Beaugrand’s letters to Descartes the following year,

he was scathing in his comments. ‘I am surprised that you decided to send me

oneofMr. N’s letters after his death, since you did not think it was worth my

while seeing them when he was still alive. Since this man was never capable of